This application relates to the reforming of the hydrocarbons pentane and higher into the reductants carbon monoxide and hydrogen for use as reducing gas. Such gases are commonly utilized for the direct reduction of metal oxides to the metallized form by the use of reducing gases. The present invention is particularly well suited to the direct reduction of iron from particulate iron or oxides. At present, processes such as the direct reduction of iron, utilize gases, such as natural gas, which consists principally of methane (CH.sub.4), with some ethane (C.sub.2 H.sub.6), propane (C.sub.3 H.sub.8), and butane (C.sub.4 H.sub.10). Natural gas also contains some higher hydrocarbons, pentane (C.sub.5 H.sub.12), hexane (C.sub.7 H.sub.16), heptane (C.sub.6 H.sub.18), etc.
Currently available natural gases in many areas of the world are displaying increasing concentrations of these higher hydrocarbons (as used herein meaning C.sub.5 and above). Such higher hydrocarbons tend to be difficult to reform stoichiometrically. Even low concentrations of such higher hydrocarbons are difficult to reform stoichiometrically without depositing carbon on the reforming catalyst.
Research is continuing to develop suitable catalysts and commercial equipment is available to extract higher hydrocarbons from gaseous fuels. However, it is desirable to be able to utilize natural gases containing higher hydrocarbons without the necessity of special treatment or use of special catalysts for such treatment.
The present invention is a method for the direct reduction of metal oxides in a shaft furnace direct reduction process utilizing gases containing higher hydrocarbons.